export default {
  // 当某月的天数
  getDaysInOneMonth(date) {
      const year = date.getFullYear();
      const month = date.getMonth() + 1;
      const d = new Date(year, month, 0);
      return d.getDate();
  },
  // 向前空几个
  getMonthweek(date) {
      const year = date.getFullYear();
      const month = date.getMonth() + 1;
      const dateFirstOne = new Date(year + '/' + month + '/1');
      return this.sundayStart ?
          dateFirstOne.getDay() == 0 ? 7 : dateFirstOne.getDay() :
          dateFirstOne.getDay() == 0 ? 6 : dateFirstOne.getDay() - 1;
  },
  /**
   * 获取当前日期上个月或者下个月
  */
  getOtherMonth(date, str = 'nextMonth') {
      const timeArray = this.dateFormat(date).split('/');
      const year = timeArray[0];
      const month = timeArray[1];
      const day = timeArray[2];
      let year2 = year;
      let month2;
      if (str === 'nextMonth') {
          month2 = parseInt(month) + 1;
          if (month2 == 13) {
              year2 = parseInt(year2) + 1;
              month2 = 1;
          }
      } else {
          month2 = parseInt(month) - 1;
          if (month2 == 0) {
              year2 = parseInt(year2) - 1;
              month2 = 12;
          }
      }
      let day2 = day;
      const days2 = new Date(year2, month2, 0).getDate();
      if (day2 > days2) {
          day2 = days2;
      }
      if (month2 < 10) {
          month2 = '0' + month2;
      }
      if (day2 < 10) {
          day2 = '0' + day2;
      }
      const t2 = year2 + '/' + month2 + '/' + day2;
      return new Date(t2);
  },
  // 上个月末尾的一些日期
  getLeftArr(date) {
      const arr = [];
      const leftNum = this.getMonthweek(date);
      const num = this.getDaysInOneMonth(this.getOtherMonth(date, 'preMonth')) - leftNum + 1;
      const preDate = this.getOtherMonth(date, 'preMonth');
      // 上个月多少开始
      for (let i = 0; i < leftNum; i++) {
          const nowTime = preDate.getFullYear() + '/' + (preDate.getMonth() + 1) + '/' + (num + i);
          arr.push({
              id: num + i,
              date: nowTime,
              isToday: false,
              otherMonth: 'preMonth',
          });
      }
      return arr;
  },
  // 下个月末尾的一些日期
  getRightArr(date) {
      const arr = [];
      const nextDate = this.getOtherMonth(date, 'nextMonth');
      const leftLength = this.getDaysInOneMonth(date) + this.getMonthweek(date);
      const _length = 7 - leftLength % 7;
      for (let i = 0; i < _length; i++) {
          const nowTime = nextDate.getFullYear() + '/' + (nextDate.getMonth() + 1) + '/' + (i + 1);
          arr.push({
              id: i + 1,
              date: nowTime,
              isToday: false,
              otherMonth: 'nextMonth',
          });
      }
      return arr;
  },
  // format日期
  dateFormat(date) {
      date = typeof date === 'string' ? new Date(date.replace(/\-/g, '/')) : date;
      return date.getFullYear() + '/' + (date.getMonth() + 1) + '/'
          + date.getDate();
  },
  // 获取某月的列表不包括上月和下月
  getMonthListNoOther(date) {
      const arr = [];
      const num = this.getDaysInOneMonth(date);
      const year = date.getFullYear();
      const month = date.getMonth() + 1;
      const toDay = this.dateFormat(new Date());

      for (let i = 0; i < num; i++) {
          const nowTime = year + '/' + month + '/' + (i + 1);
          arr.push({
              id: i + 1,
              date: nowTime,
              isToday: toDay === nowTime,
              otherMonth: 'nowMonth',
          });
      }
      return arr;
  },
  // 获取某月的列表 用于渲染
  getMonthList(date) {
      return [...this.getLeftArr(date), ...this.getMonthListNoOther(date), ...this.getRightArr(date)];
  },
  // 默认是周一开始
  sundayStart: false,
};